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A

Acidity (of water)
Acidity is the Latin term for the level of acidity or acid content of a liquid. For water this content complies with a specific amount of a strong acid, specified as a milli-equivalent per litre of water, which is required to titrate the water sample to a pH value of 7 (neutral).

aerobic
name for the mode of life of organisms which require oxygen to live or chemical reactions which are only possible with oxygen (micro-organisms). Aerobic sewage purification, for example, is made in an activated sludge plant via micro-organisms with the addition of oxygen (e.g. via oxygen gassing).
An aerobic condition refers to a condition of water which contains sufficient dissolved oxygen with the result that aerobic bacteria can survive. If, however, there is only undissolved bonded oxygen, we speak of an anoxic environment. If there is no oxygen, the system is anaerobic

anaerobic
Term for the mode of life of organisms which require no oxygen to survive, and for a chemical reaction which takes place without the presence of oxygen. Anaerobic cleaning of sewage and clearing sludges also takes place i.a. in digester towers and is especially applied by industrial companies to save energy, particularly for strongly organically contaminated sewage. The gas (biogas) resulting in the digestion process can be used for heating. However, if there is undissolved bonded oxygen, we speak of an anoxic environment. If there is dissolved oxygen, the system is aerobic.

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Anodic Oxidation
The term, anodic oxidation, combines two different sections of decontamination which have a different weighting depending on the respective manufacturer. Such systems are provided as small units for single dentists’ chairs through to large central systems. One active principle is based on the recirculation of water, in which it is led repeatedly across an anode, on or at which the micro-organisms are destroyed. Recirculation systems are usual in the hot water range. To decontaminate cold water, which in principle is possible, an appropriate recirculation system first has to be installed. Recirculation of water every 2 to maximum 3 hours must be ensured via appropriately large pumps.

Apart from an insufficient function of elimination effect, the biofilm growing behind the unit in the water system can not be detected, resulting in recontamination of the water. Therefore, chlorine or hypochlorite is also produced from a saline solution which is added to the drinking water at an amount permitted pursuant to drinking water regulations. By means of continuous measuring of ‚chlorine concentration’ in the recirculation water, the correct amount is added. The purpose of this process is to equalize the so-called chlorine demand. As stated above, a disadvantage is that maximum chlorine concentration permitted pursuant to drinking water regulations is only sufficient for the destruction of free floating bacteria. Studies made of the process of anodic oxidation in dentists’ chairs have shown that there was only sufficient germ reduction when the chlorine concentration was considerably higher than the official limits. Decomposition of the biofilm is not possible. As such, no sustained cleansing success has yet been achieved. The application of carbon electrodes has also not led to any improvement.
(Source:Krh.-Hyg- +Inf.verh.24Heft 6-2002)

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B

Bacteria
From the Middle Ages through to the present day, a large number of people living in Europe have died as a result of epidemics such as the plague, cholera and leprosy. The viruses of these deadly illnesses (yersinia pestis, vibrio cholerae, mycobacterium leprae) were first discovered much later together with evidence of their potential danger to health. Historians are of the opinion that bacteria have played a significant role in the political and cultural development of Europe, since probably entire wars have been decided as a result of the influence of these micro-organisms. For example, Napoleon’s military campaign against Russia is said to have failed on account of more soldiers dying from typhus caused by the virus, ricksettsia, than in battle. This brought about the fall of Napoleon.

The reason why bacterial infections in the Middle Ages developed into epidemics was that viruses spread via drinking water or via parasites such as lice. Viruses are often egested or passed on by affected persons, and hygiene as we conceive it today was not known in the Middle Ages. Inadequate separation of drinking water and faecal-contaminated ground water from pit drainage and the passing on via parasites led to a cycle of viruses which hardly anyone could avoid. Weakening of the body from hunger and hard physical work paved the way for numerous lethal infections.

In addition to classical epidemic viruses which today are almost extinct in Europe thanks to ideal drinking water processing and sewage disposal as well as hygiene standard, there are still some viruses which may lead to infections. Certain viruses mainly affect individual organs and are responsible for specific disease patterns: pneumonia via pneumococci or klebsiella pneumoniae, meningococcal meningitus, abdominal infection via escherichiacoli or enterobacter aerogenes, infected wounds via staphylococcus aureus, lethal poisoning of the nervous system via clostridium botulinum. The bacteria, helicobacter pylori, is suspected of contributing to the development of stomach cancer. The ability to cause a disease or infection is often based on special metabolic activity of the bacteria which enable them to infect the respective tissue or to cause a physical reaction which leads to a weakening of the human body. For example, the cholera virus, vibrio cholerae, egests a toxic substance in the human intestinal system which leads to crampy dysentery and thus to a high loss of water and electrolyte from the body. Clostridium botulinum produces the strongest natural toxic substance discovered up to now: Botulinus toxin. This toxic substance prevents stimulation in the nervous system resulting in paralysis of the muscles, which can also affect the functioning of the heart. Staphylococcus aureus has certain enzymes which reduce protein and thus exacerbate infection of wounds.

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In contrast to mould, the spreading of bacteria is mostly linked to one conductor. Disease germs are passed on via sop-called drip infections or direct physical contact via the mucous membranes. Only few types are transferred via air, since bacteria has hardly any protection against the eliminating effect of UV light from colours, nor do they have protection against drying out from thickened cell walls. This means they are especially vulnerable in the air and leads to relatively swift elimination of bacteria on dry surfaces. The most significant feature of the micro-organisms or bacteria is its tiny size of a few thousandths of a millimetre. This tiny size and the surface/volume ration of the bacteria cell has a direct impact on metabolism typified by a high substance turnover and extreme flexibility. The bacteria cell provides little space for storing a large number of enzymes or protein. High adaptability of metabolism, however, means that those enzymes are produced required for the utilizing of a nutrient, and its production is only inducted via the existence of such a nutrient. This means that a wide range of nutrients can be utilized, and bacteria can adjust to prevailing environmental conditions and adapt continuously. This capability also has an impact on interaction with the environment of the bacteria, since they can often egest toxins and have a high reproduction rate.

Such features are experienced by humans especially with regard to viruses. If bacteria find good conditions for growth, it doubles its numbers within just a few minutes to hours, with the result that millions of offspring are produced within a day from just one cell. Their tiny size and adaptability also means that bacteria are to be found everywhere and can settle in almost any medium; whether it be arctic regions or on the bottom of the ocean or in higher atmospheric layers. However, the largest spread and variety of bacteria in the world is to be found in the ground. The respective environment influences the type or bacteria or micro-organism to be found. Particular features of impact include e.g. existence of oxygen, the pH value (acidic or alkaline) or the water content. Though most humans link bacteria with viruses, the majority of bacteria are useful.

The production of dairy products with lactic acid bacteria (lacttobacillaceae), the regeneration of sewage via the decomposing capacity of various bacteria groups in sewage plants, the production of chemical basic substances and the contribution of bacteria to human digestion are processes which have a positive effect on our lives. The mineralization of nitric, sulphur and carbon compounds via bacteria transforms these elements into a plant available form ands natural metabolic cycles are closed. Without bacterial activity, life on earth as we know it would be inconceivable. In contrast to the variety of potential metabolic capacity, the external form of bacteria is restricted to a few basic forms. Except for very few exceptions, the microscopic pattern of all bacteria reveals a spherical or stick-like cylindrical form. Spherical cells are called coccoids. These include the genera of micro-coccus. Streptocioccus or staphylicoccus. Rods are usually of the genus of pseudomonas or bacillus types. Bent rods are of the genus, vibrio. Long, winding rods are termed spirilla. Many bacteria genera can become active via flagella. Flagella are long, fibre-like structures on the bacteria surface which pull or push a bacteria cell via rotation, similar to that of a ship’s propeller. Several flagella can be distributed at the sides of bacteria or bundled at the end of a cell (polar). Some types have only one polar flagellum. The flagella can rotate at a speed of approx. 3000 r.p.m. and can move the cells by 300 to 3000 times the cell size per minute.

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Bacterial exposure
Microorganisms, especially bacteria are ubiquitous in our environment. Micro-biological or bacteriological water examinations are primarily intended to provide early recognition of the existence of untypical water conditions. An increase of harmless bacteria can therefore be an indication of general contamination of water. On the other hand, the occurrence of pathogenic bacteria from the recording of indicator bacteria is also part of hygienic water assessment. Routine bacteriological examination includes the definition of total bacteria, the number of coliform bacteria, the enterococci, escherichia coli and other negative effects.

Biofilm
(biofilm) Layer of settled living and dead micro-organisms. Biofilms develop when micro-organisms (e.g. bacteria, algae, protozoa) settle on boundary surfaces between gas and liquid phases (e.g. in free water surfaces), liquid and solid phases (e.g. gravel on the river bed) or at liquid/liquid phases (e.g. oil drops in water). A thin, mostly closed film forms on the boundary surface in which micro-organisms are embedded.

Other terms for biofilm include: aufwuchs, flower, sewer slime, slime layer. The boundary surface on which biofilm forms is called a substratum. The majority of micro-organisms in nature live in the form of biofilms. From a technical point of view, biofilms can have both positive and negative effects. An advantage of the biofilm is that it self-cleanses water, negative effects ensue if biofilms e.g. cause material destruction (biogenic corrosion). Biofilms grow in different ways. In some cases, dense, closed biofilms develop with a relatively even boundary surface to the overflowing fluid. However, the boundary surface can also be very uneven, if for example bacteria forms like fibre (filament) into the fluid or if the substratum is settled with protozoa (e.g. vorticella) or higher forms of organism. The current conditions around the biofilm play a significant role. Formation of biofilm commences when a cell settles on a boundary surface and proliferates.

Various mechanisms can be responsible for adhesion of the cells to the boundary surface. Van der Waals’s forces are of special importance, as well as electrostatic attraction and hydrogen bonds. In fact, very boundary surface provides adhesion potential for micro-organisms. Bonding is often assisted if the boundary surface is already settled with organic polymers (e.g. polysaccharides). Such polymers are normal of biological origin. They originate from the mucous layer which forms around bacteria cells, occasionally partially or completely separates and is bonded adsorbently when contact is made with surface boundaries. As a result of the proliferation of cells settled on a surface, organisms spread. The surface boundary is first settled in laminar form as a film (biofilm). The biofilms develop simultaneously or later as multi-layers and finally form three-dimensional structures with boundaries which vary in sharpness to the phases adjacent to the biofilm (solid, liquid, gaseous). The resultant biofilm matrix can be closed, or contain pores, caverns or channels. The latter is often observed in the early stage of biofilm development. The orhganism cells in the biofilm are mostly embedded in a slimy matrix of extra-cellular, polymer substances (EPS). A transfer situation is found in many cases towards the boundary surface. This especially applies for the boundary surface “biofilm-water”. In the core area, the biofilm is compact (basis biofilm). The edges, however, are often formed unevenly (surface biofilm). Micro-organisms grow into the liquid phase (e.g. fiber-form growing bacteria, vorticella), and ‚valleys’ or ‚peaks’ are created.

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C

CFU = colony forming units Abbreviation for colony forming units. A parameter of the bacteriological quantitative water examination recording of viable and augmentable microorganisms. It specifies how many colonies are visible in a 6 – 8 times magnification on a defined nutrient medium after a specific incubation time and incubation period. The colony number can also contain additional information of the level of contamination of water. The value is mostly related to sample volumes and thus specified as a concentration figure (e.g. CFU/100ml).

Chemical Disinfection
With e.g. chlorine, ozone, silver or copper ions. Disinfectant substances are added via dispensing units or consumption electrodes which can be collectively termed as chemical disinfection. The adding of means or ions is made within the scope of maximum limits permitted pursuant to drinking water regulations. In principle it can be said that such amounts permitted do not enable the reduction of biofilm or the destruction of released plaque. Only floating micro-organisms can be destroyed. In addition, practical zero effect has been found when silver or copper ions are added via consumption electrodes in cold water. To achieve a reduction of biofilm, concentrations are required which corrode piping and which lead to odorous fumes and allergies and which exceed the limits specified in the drinking water regulations. Such measures (e.g. rinsing with hydrogen peroxide) are only feasible as a special measure if a hospital, hotel or apartment building is inoperative, but doo0 not result in permanent success, and have to be repeated at regular intervals.

Chlorine, Cl
Chlorine is one of the most reactive elements. It can react strongly with reducing, organic and alkaline substances. Chlorine solutions have a corrosive effect and react with nearly all metals under combustion, if these are finely spread. Dangerous reactions ensue partially on combustion with saturated and unsaturated hydrocarbons, ammoniac, amines, fluorine, carbon monoxide, sulphur dioxide, hydrogen sulphide and hydrogen. Together with water, chlorine forms hydrochloric acid. Chlorine is one of the most important raw materials in the chemical industry. Production of chlorine normally is made applying an electrolytic process (amalgam process, diaphragm process, membrane process). Chlorine is used in the following fields i.a.: PVC and solvents. It comes into direct contact with water when used as a pesticide, flame retardant, bleaching agent and as a means of disinfectant.

Chlorine is classified in Water Hazard Class 2. If larger amounts penetrate into the ground or ground water, drinking water may be endangered. Chlorine has an effect as toxin for fish (lethal concentration LC = 293 vpm). It can also be hazardous for the environment if larger amounts are released into the atmosphere. Together with moisture of the mucous membranes, chlorine forms active oxygen and hydrochloric acid. Both of these can harm tissue. Inhalation of around 3-6 ppm leads to irritation of all mucous membranes with coughing and lacrimation. In case of longer exposure, it can lead to hemoptysis and shortness of breath or signs of asphyxia. Liquid chlorine is caustic to the skin. Chlorine is also used i.a. as a disinfectant in Germany, especially in swimming pools and domestic detergents. It is also used in the form of chlorine dioxide in water processing. The measuring of chlorine content to set the disinfectant concentration (e.g. in swimming pools) is made i.a. using the DPD method.

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Chlorine dioxide
Chlorine dioxide (ClO) is one of the higher quality oxygen compounds of chlorine, together with chlorite and chlorate. Chlorine dioxide is a very strong oxidant.

Coliform bacteria
Coliform bacteria are specific bacteria or bacteria groups alive in human or animal intestines, comprising the coliforms, faecal coliforms and e-colis. Evidence of coliform bacteria in drinking water is an important indication that contamination with excrement has occurred and other viruses may exist.

Colilitre
Colilitre, the smallest water volume in ml in which escherichia coli can be detected; bacterial measurement for contamination of water with faeces.

Continuous heating to 60°C
or periodic heating (once a month) to 70 °C. The most widespread system is that of the heating of water pipe systems. Recirculation of the hot water and continuous maintenance of a return temperature of 60 °C is normally installed in private homes today. This is based on process sheets of the DVGW (German Gas and Water Association). However, the parameters specified are only observed in a minority of cases. Flow temperature directly behind the heating is often 60 °C, but not the temperature at the extraction point or in return, with the result than bacterial growth can develop in these pipe sections. An attempt is made to counteract this via periodic temperature increase to 70 °C. In addition to high energy and personnel costs, intensive calcinations and corrosion of the pipes and taps are all disadvantages of this inadequate method; after approx. half a year, plants are again contaminated. Even in the case of ideal execution of heating method, essential disadvantages remain: insufficient effect against biofilm, no effect against coli from unused lines, and above all restriction of hot water, cold water can not be heated to 60/70°C, since then it is no longer cold water!

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D

DIN Norms
The DIN is a registered non-profitmaking association located in Berlin (DIN Deutsches Institut für Normung e. V., founded in 1917). The DIN is the institute responsible for norms work in Germany and represents German interests in worldwide and European standards organisations. This status was recognized in the contract with the Federal Republic of Germany dated 5. June 1975. The DIN is the round table at which the manufacturers, trade, craftsmen, service companies, science, technical supervision, state i.e. everyone interested in standardization, meet, to establish state of the art and to include such new findings into German norms where applicable.

DPD
Abbreviation for simple method for determining the concentration of chlorine in water. The measuring method is also used i.a. in swimming pools. N.N-diethyl-1.4-phenylendiamin (DPD) oxidizes with the existence of free chlorine forming a red colouring. Bonded chlorine also forms a red colouring if there is iodine (total chlorine definition). The chlorine concentration is recorded by visually by means of a comparator using a photometer (calorimeter). Using the so-called DPD-1 test, the free chlorine is content is subjected to sampling, in which the DPD 3 test records the total chlorine content composed of free and bonded chlorine.

E

Enterococci
Enterococci are allocated to the group of lactic acid bacteria. In our environment, enterococci exist in animal and humans as well as in conventional food such as cheese and raw sausage. Enterococci can be an indication of by hygienic conditions during production and processing. They can indicate possible contamination of water and are specified as examination parameters in drinking water regulations. No enterococci may exist in one hundred millilitre samples. They are gram-positive, aerobic cocci which differentiate from staphylococci by way of their chain form, which can be seen under a microscope. Representatives of the cocci group mostly produce haemo-toxins and are known as viruses or causers of unspecific food poisoning. Its pathogenicity is proven by way of its serological or haemolytic reactions.

Escherichiacoli
Escherichia coli (E. coli). Intestinal bacteria of humans existing in many stems, named after the physician, Th. Escherisch, gram-negative bacteria in the colon of healthy humans and animals; contribute to digestion and decompose carbohydrates of nutrients forming acid and gas. Indicator for faecal contamination.

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Eschericha coli and coliforms (e.g. Enterobacter aerogenes):
E.coli is a "sure indicator" for faecal contamination in water, since it has a long life outside the colon, in comparison to other entero bacteria, and can be well cultivated. The term, Coliforms, is used for entero-bacteriacaeae typified by gram-negativity, short stick form, aerobic or facultive anaerobic metabolism and inability to form traces. They are only ‚indicators’ for faecal contamination of water. The most important of these is enterobacter aerogene (formerly also klebsiella aerogenes). Both ‘indicator bacteria’ can use lactose as a source of carbon, which differentiates them from other bacteria on suitable nutrient media.

F

Faecal streptococci
Are bacteria and, like escherichia coli obligates, part of the intestinal flora of humans and all other warm-blooded creatures. They are also used as control organisms. They must not exist in 100 ml drinking water samples.

Fungus, mushroom
Fungi are not a uniform group of related agents in biology. Clear definition of fungi is considered to be extremely complex. Fungi normally is the term used for single-cell or multi-cell or cynocytical (cave-cell, whose multi-nucleus cells lie unseptated in a cavity formed by the cell wall) organisms with real cell nucleus without the ability for photosynthesis and without active movement. They survive in almost all regions of the world heterotrophically mostly from the decomposition of dead organic substances or as parasites from living organisms and thus also participate in the natural cycle of matter. The majority of fungi grows in the form of microscopically small, branched threads (hyphens). Some of them form spherical or elliptical sprout cells. This is especially apparent in yeasts. Cautious estimates state there are at least 100,000 different types of fungi. The fungi occurring in sewage water are called sewage fungus.

G

Generally accepted rules of technology
(AaRdT) a term used in technical and environmental protection law, which assumes the standard fort he application of a process to bet he recognition of such by the majority of specialists active in a specific field. Also refer to State of the art.

Germs
Pathogenic germs (e.g. cholera, typhus, paratyphus, dysentery viruses) must not be found in drinking water. Coli bacteria (e.g. escherichia coli) which is often to be found in the intestinal system of humans and animals indicate faecal contamination if they exist in water. The smallest water volume specified in ml in which Escherichia coli is detected is termed as coliltre. There must be no Escherichia in 100 ml drinking water.

I

Indicator microorganism
Microorganisms or plants which provide information on ground or water quality and possible contamination on account of their existence (especially the frequency of their occurrence). For example, coli bacteria in water indicates faecal contamination. Analysis of plants at a location can provide information on e.g. saline content, nitrate content, lime condition, acid value of the ground or water through to climatic and environmental factors.

Infections
An infection is generally the penetration of microorganisms or viruses into another organism, and in humans this can lead to infectious disease. Workers in a sewage plant or canalization system can be infected in various ways via the numerous microorganisms in their professional environment, i.e. they can become infected. The relevant infections in this field are categorized differently in varying lists, e.g. in:
Oral infections
Cutaneous infections
Parenteral infections
Infections via air

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Oral infections: Numerous microorganisms in sewage water and therefore also in sewage sludge originate from excrement of humans and animals and can cause infections if taken in orally. Studies have shown that people who start work in the sewage industry suffer far more frequently from dysentery than the general public in their first half year of work, but then become resistant.

Cutaneous infections: Transfer is made via skin wounds or intact skin.

Parenteral infections: Skin lesions are normally populated by sanies agents from water if they are not treated professionally. Deeper skin lesions can be contaminated from sewage, with the risk of tetanus. Infections via air: aerosols with a high concentration develop in sewage plants. Most agents in sewage water are not transmitted via air. On account of addition of medicine, there is an increase in bacteria in the sewage water resistant to antibiotics. It has not yet been clarified as to whether this also involves an increased risk to sewage workers. Sewage plants which formerly handled tannery sewage could theoretically still contain living anthrax bacilli according to some studies. However, there have been no cases of this disease up to now. Legal standards for protection against infection are summarized in the Infection Protection Act (IfSG).

Infection Protection Act - IfSG
The German Infection Protection Act (IfSG) has regulated the prevention and fighting of infectious diseases since 1. January 2001. It was passed by the German parliament with the approval of the upper house on 20. July 2000, published in the Federal Law Gazette on 25. July 200 and came into effect on 1. January 2001. As a result, the following laws and regulations were replaced: federal epidemic law, law for the fighting of venereal diseases, laboratory report regulations, regulations on the expansion of registration to humane spongiform encephalopathies, first regulation on the execution of the law on fighting venereal diseases, second regulation on the execution of the law ion fighting venereal diseases.

The Infection Protection Act is a federal law in the field of risk prevention, which is normally a matter for the federal states. Since risk can spread very quickly beyond state borders in the case of epidemics and infections, a national regulation appears more useful. The Infection Protection Act also makes adjustment to Community Law (Section 11). Important sections include prevention (Section 4) and Fighting (Section 5) of infectious diseases, and the respective registration procedure (Section 3). In situ from the Latin: treatment on location. This normally refers to the use of a process or measuring method in which the actual process is not moved. For example, in ‘in situ’ cleansing of contaminated ground water conductors a process is referred to which is placed directly into the ground water conductor without the ground water being pumped out. In accordance with this, a process measuring and control technology termed ‘in situ’ is used in the ongoing process and not made by way of sampling or bypassing outside the actual process.

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L

Legal foundations and authorities
The water Resources Act and European Water Guidelines form the legal foundations concerning water, the water industry and public handling of water resources in Germany.

Legionella, legionells
Legionella are rod-shaped and mostly survive in stagnant warm water (25° C to 50° C) and only die at temperatures above 60 °C. Hot water tanks and water pipes rarely used can provide ideal conditions for the spreading of legionella. Legionella become a risk for humans if they enter the lungs in large volumes via finely sprayed water (aerosols, e.g. when showering or using whirlpools, inhalation units and waterpicks, as well as via air conditioning. Serious illness to the respiratory system which are a risk to life can be caused. It may also lead to serious, atypical pneumonia (Legionnaire’s Disease). However, according to current findings, drinking water infected with legionella is not a great risk. In case of illness with a suspicion of legionella, the doctor should be informed of a possible legionella infection. Experts estimate that around 700,000 people in Germany are infected each year with legionella, 70,000 of these suffer from a flu-like form, 7,000 suffer serious pneumonia with around 2,000 deaths. Legionella are often diagnosed too late by doctors. However, a comparison with the approx. 200,000 cases of pneumonia each year shows that the risk of suffering from serious legionella infection is relatively small.

M

Multi-resistant pathogens – How can you protect yourself from hospital infection?
In terms of statistics, an average of 3.5 – 11.6 hospital infections occur in hospitals for acute cases in Europe. The European Centre for the Prevention and Control of Diseases (ECDC) specifies three million noso-comial (in-hospital) infections per year in Europe in its 2007 report. Between 4,500 and 7,000 people in Italy die each year from infections originating from a stay in hospital. This means that Italy is about average in such cases. Between 10,000 and 15,000 people in Germany die each year because they suffered a serious infection during their stay in hospital. The total of in-hospital infections is estimated at 400,000 to 600,000 per year. The German Society for Hospital Hygiene assumes that around four to nine per cent of all patients entering clinics are infected by in-hospital infections. The most frequent cases involve wound infections after operations. These are followed by urinary passage infections, serious respiratory system infections, including 60,000 cases pf pneumonia.

These figures correspond with experience made in other countries. In England, 320,000 infections were recorded, and in the USA the figure is 1.7 million per year. According to another source, around 3 million people in Germany are infected each year from stays in hospital. Around 50,000 die of such infections.
On average, hospital infections cause four extra days in bed and additional costs of 4,000 to 20,000 Euros.

The agents most feared are antibiotic-resistant staphylococci, escherichia coli or enterococci – all normally harmless provided they do not proliferate. They are, however, a real danger for persons with a weak immune system.
This is why nursing homes, kindergartens and rehab facilities are included in this group.

P

Pathogens
Pathogens with faecal origin can be transferred via drinking or bathing water, and can lead to individual disease or explosive epidemics, depending on the pathegenic concentration and the number of persons infected. These diseases come about by way of the pathogen being transmitted directly via faecal-oral way via contaminated faeces on hands placed on the mouth, or indirectly via water or food. In addition to bacterially caused diseases such as cholera, dysentery and typhus, the infectious diseases transmitted via water include viral diseases siß0ucb´h as gastroenteritis, hepatitis and protozoa, such as giardiasis. When bathing in swimming pools or indoor swimming polls, virus-related plantar verruca and parasite-related cercaria dermatitis are also transmitted.

Pathogens in water:
Only few pathogens can be transmitted via water compared to the total of pathogens which exist. The pathogens occurring in water must have a special resistance to environmental influence. Water pathogens are divided into different groups: these include bacteria of faecal origin which include types which can bring about classical water epidemics such as cholera (vibrio cholerae), typhus (salmonella typhi), parathyphus (salmonella paratyphi) and bacterial dysentery (shigella). Such pathogens can survive in water for several weeks. Viruses and protozoa are also water pathogens which are transmitted faecal-orally. As a result, viruses can cause polio (poliomyelitis-Viren), gastrointestinal diseases (Norwalk virus, Rota virus), and protozoa can cause amoebic dysentery (entamoeba histolytica), giardisis (giardia lamblia), cryptosporidiosis (cryptosporidium parvum). There are also bacteria of non-faecal origin which can cause, for example, outer ear inflammation (pseudomonades), wound infections (aeromonades), legionellosis (legionella) etc. Diseases transmitted faecal-orally endanger especially humans in using water as drinking water and bathing water. Organisms proliferate in the intestine in large numbers, are egested via the stool of humans or other warm-blooded creatures and then return to the humans via detour via water. This means that humans are endangered via contaminated water in the form of drinking water or bathing water.

Production and Application
On account of the oxidizing effect of chlorine dioxide, it is often used as a disinfectant. Chlorine dioxide is normally used as a diluted solution to prevent danger of explosion. However, the chlorine dioxide solution can not be stored for long, and must be used immediately. Therefore, production must take place at the place of use. New twin-component processes now provide exceptions, in which two liquid components are simply mixed by hand. Such solutions are non-explosive and can be stored without risk individually. Chlorine dioxide is an oxidizing biocide, and is not a metabolic toxin; this means that it damages micro-organisms by interrupting transport of nutrient via the cell walls, and not by interrupting metabolism. Its MAK value is 0.1 ppm. Chlorine dioxide is used as a disinfectant in drinking water processing plants as well as sewage purification, and is preferred to pure chlorine due to its greater effectiveness. The advantage of the chlorine dioxide process is normally that no haloforms or chlorophenols are formed, and no chloramines are formed.

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Entry of pathogens into water:
The pathogens dangerous for humans, mostly faecal-oral, enter water in the following ways:
- via outlets from sewage plants (contaminated water from households and the trade,
- via sewage water direct entry (contaminated water from the industry and trade, e.g. dairies, abattoirs),
- via storm water overflow,
- from various sources (such as avulsion from agricultural areas, water vehicles, water fowl).A significant and surprising factor is that the sewage water regulations do not include any hygienic microbiological requirements. The dangerous properties of human-pathogenic pathogens are not mentioned in the paragraph of the water household law regulating sewage water. The question is: why are microbiological parameters not considered? However, there are conditions concerning disinfection for some origins. These include certain hospital wards, tuberculosis clinics, tanneries, animal elimination plants and gene-technology plants.

pH value
The pH value is a measurement for H ionic activity. The pH value is defined as: 1 pH= -log a(H ), whereby ionic activity a is in relation to the concentration c via the activity coefficient f: 2 a = f c. In words, the pH value is the negative value of decade logarithm (log) of measured activity of hydronium ions in an acqueous solution. In simple terms, the pH value is a measurement of the concentration of acid (pH < 7) or and (pH> 7). a pH value of 7 is considered "neutral".

Humans or animals normally tolerate life conditions in tight pH value limits (e.g. between 5 and 9). As a result, waste water which is to be fed into canalization or a receiving water course must have specific pH value limits. The pH value alone only partially reveals the acid or base volume which can become corrosively or physiologically effective. For this reason, the acid capacity or base capacity of waste water has to be defined in specific cases. Biological sewage cleaning using microorganisms must mostly be made in the range pH 6 – 8, since most microorganisms are damaged or are not active outside this tolerance range. Therefore a pH value regulation or neutralization is executed prior to the biological stage in respective sewage works. Since many decomposition processes also have an influence on the pH value, suitable regulation is complex in the case of changing compositions of sewage. For some decomposition processes there is an ideal pH value or pH value range which may deviate from the neutral value. The pH value can be measured using commercial electrodes or more simply using indicators and their course of colouring.

Processing of water
Qualitative change in water to adjust its quality to the respective purpose required, e.g. process or drinking water. Because water is so often changed in its natural cycle with regard to bacterial, biological, chemical and physical aspects with the result that it is often not useable as drinking water or for commercial purposes, it has to be processed fort he respective purpose involved.

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Protozoa
Single-cell microorganisms with at least one nucleus. They are also termed as original animal, protozoa and basis of the animal kingdom, and comprise approx. 20,000 types. Protozoa mostly live in water, partially floating or fixed, partly colony forming or as parasites, including epidemic pathogens, e.g. malaria, sleeping sickness, amoebic dysentery. Protozoa occur cumulatively in sewage sludge and are part of almost all sewage with biologically degradable substances.

Pseudomonads
Pseudomonas is a genus of rod-shaped, moving gram-negative bacteria. They need oxygen to grow and are ubiquitous in our environment (‘puddle germ’).

Clinical significance
This genus is clinically very important because the majority of its members are resistant to antibiotics. They are also able to form biofilms in the case of higher cell density (slime) which protect them against phagocytes and antibiotics. Although bacteria of this genus seldom cause illness for people with an intact immune system, they can cause infection of wounds, respiratory system, urinary passage, pneumonia as well as sepsis and heart disease to patients with a weak immune system (for example in hospitals, so-called hospital germs). Wound infections are typified by their green colouring and their odour. Patients with the genetic disease of cystic fibrosis (muscoviscidosis) are most at risk, for whom pneumonia is the most frequent cause of death. Therapy can be provided via acylamine penicillins such as azlocillin and piperacillin, cephalosporine as of the third generation (especially ceftazidim and cefepim), recent fluocinolones and carbapeneme. The genome has been decoded.

Pseudomonas Genome Project Clinical studies concerning pseudomonads innoculation have nee carried out for some time. Pseudomonads normally survive saprotrophically, i.e. from dead organic material. However, in physiological terms they are very flexible and can occur as an opportunistic pathogen in weakened plants and animals. Plant pathogenic stems exist from many pseudomonad types, so-called pathovars. The virulence genes are mostly mobile and can easily be transmitted from one psuedomonad type to another, and also to distant related bacteria.

R

Redox potential, oxidation-reduction potential
Indicator for the definition of self-cleansing potential of water.

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S

State of the art
State of the art is a technical term referring to the technical potential at a specific moment in time, based on well-founded findings of science and technology. It is included in many regulations and contracts and is exactly defined via regulations concerning legal formalization. State of the art also includes the fact that it is economically viable. This does not mean that each company can afford state of the art, but most companies in the respective industrial sector.

State of the art is the development status of advance processes, facilities or modes of operation concerning the practical suitability of the measure with regard to respective targets (e.g. targets of protection at work, environmental protection, safety for third parties, cost-effectiveness: factors required to achieve a generally high level in relation to aspects to be considered) which in total appears to ensure that such exists. However, it has not been sufficiently tested over a period of many years and mostly only known to specialists, which is why normally only observance of recognized rules of technology is required by contract ion the building industry. In addition, ‚state of the art’ in patent documents refers to those processes or facilities in connection with the content of the document which are already respectively known and from which the invention/technical innovation is to stand apart from.

U

Umweltbundesamt (Federal Environmental Agency)
The Federal Environment Agency is the scientific environment authority in the business field of the Federal Ministry of Environment. Nature conservation and reactor safety (BMU) with a variety of topics, whereby work is focussed on the protection of humans from damaging environmental influence.

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UV water disinfection
Process for the disinfection of i.a. drinking water and swimming pool water using UV radiation. In southern regions it is also used for the disinfection of sewage. The micro-organisms in the water are subjected to germ-killing, ultraviolet radiation of special wavelength. This is intended to rid them of their ability to breed. Normally, UV water disinfection is made continuously in flow units, whereby ideally all pathogens absorb a lethal dose of UV energy. This dose is the product of UV radiation strength and the dwell time of water in the flow unit. UV water disinfection is considered effective and safe, and neither changes the taste, colour or odour of water. Water treated in this way can be used commercially and as drinking water.

V

Viruses, virus
Viruses are among the smallest pathogens. Despite their small size, viruses are not allocated among microorganisms, since they can not reproduce themselves, but rely on the metabolic capacity of their host cells. They consist of nucleic acids (molecule containing genetic information, e.g. DNS or RNS). All viruses can spread via water which enter the environment from humans as well as all animal forms, plants and bacteria. Simply structured viruses which consist only of nucleic acid (genetic material) and protein capsid (egg white) can survive in the environment for up to one year ore longer (persistence) and enter the water cycle. Human pathogenic ‘enteral’ viruses’ are mostly egested by sick or infected persons in their stool and enter domestic sewage. They are very resistant to sewage cleansing methods and measures for drinking water processing.

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W

Water hardness
Water hardness describes the concentration of ions of calcium and magnesium. The content of calcium magnesium salt defines the properties of water: the higher the respective share, the harder the water. Calcium and magnesium are therefore also referred to as hardness components, and their existence defines the ‚total hardness’. A German hardness level (1° dH) corresponds to 10 mg calcium oxide or 7.19 mg magnesium oxide per litre of water. Hot water and heating systems require soft water, since otherwise boiler scale settles. Dosing of washing detergents is also dependent on the water hardness, since the effect of various surfactants are dependent on the water hardness, especially linear alkylbenzene sulphonate (LAS). Hardness components reduce the washing effect of detergents. Appropriate dosing instructions have to be specified on the respective washing powder packaging. Soap foams badly in hard water because it forms unsolvable calcium and magnesium salts. The ffect of water hardness is therefore softened in most washing detergents by adding phosphate. In technology, softening is achieved i.a. via:

Distillation,
Precipitation with soda or sodium phosphate, with ion exchanger via so-called softening plants, in the household via softening agents contained in washing powders and detergents. In the Federal Republic of Germany, the level of hardness is divided into four categories: They are defined in the Washing Agents and Detergents Act.

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Hardening range millimol total hardness °dH
1 < 1,3 < 7
2 1.3 – 2,5 7 - 14
3 2.5 – 3.8 14 - 21
4 > 3.8 > 21

over 30°d = very hard

In addition, normal classification is stated as follows
0-4°d = very soft
4-8°d = soft
8-18°d = medium hard
18-30°d = hard
over 30°d = very hard.

Information on respective water hardness ranges is available from the local water supply companies. The water supply companies have to publish the hardness range of drinking water provided once a year. On account of the health significance of water hardness, drinking water must not be softened below 1.5 mmo/l, or 8.4° dH. Ion exchangers are mostly used for softening in households. These have to be regenerated with common salt and thus have a negative effect on sewage. At the same time, sodium concentration in the drinking water also increases. The complexometry is a definition method for total hardness of water.

Water as drinking water and product
The water useable as drinking water is categorized into storm water, surface water in rivers, lakes, dams, ground water, mineral water and spring water. Use of the water is regulated in the Water Resources Act (in Germany, Austria and Switzerland). In central Europe there is reliable, cost-effective and high-quality water supply, mostly from public suppliers. Tap water mostly comes from the local region, and the community supplier is responsible in terms of ecological properties. The water market worldwide is experiencing growth like practically no other sector. That is why private suppliers have a great interest in defining water as a product in order to penetrate markets. Even if normal drinking water is not directly a product, many organizations claim there is indirect water export as a result of globalization, especially in third world countries. For example, this means that to cultivate bananas, 1,000m² area is required. As a result of production increases for export purposes, water is missing for the local population (source: Wuppertal Institute).

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Water consumption
Water consumption is water required for human consumption. This comprises direct human consumption (drinking water) as well as daily life (washing, cooking etc.) and the water requirement specified for agriculture, trade and industry (refer to Process water). As the word, consumption, suggests, water is changed in this process in terms of its volume and quality. Water consumption is therefore not only a parameter for water volume required, but also for disposal (canalization, sewage plant). Water demand in Germany in 1991 amounted to 47.9 billion m³, of which 29 billion m³ alone was used as cooling water ion power plants. Around 11 million m³ was used directly by industry, 1.6 billion m³ by agriculture. Only 6.5 billion m³ was for drinking water supply. The average water consumption amounts to approx. 130 litres per inhabitant per day (of which about 1 litre is for drinking, in addition to Cola, beer or other beverages which also contain water).

Water treatment, water processing
Water treatment is a term which mostly refers to process steps via which natural water is processed into drinking water. In a further sense, however, it also refers to treatment methods by which water is purified, e.g. in processing:
Sewage water
Industrial water
Drinking water
Swimming pool water
Cooling water

All methods known in process engineering can be used in water treatment, including e.g.:
Biological processes,
chemical processes,
mechanical processes and
thermal processes.

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Water supply:
Supplying people with clean water is not only a logistic problem for those in developing countries. Only 0.3 % of worldwide water resources is available as drinking water, which is 3.6 million km³ of a total of approx. 1.38 billion km³. To alleviate water shortage in countries with little storm water, somewhat eccentric ideas have been conjured up: for example, it was proposed to tow an enormous iceberg across the ocean which would only melt to a small degree and to collect drinking water from the melting iceberg.

Drinking water is fresh water with a high level of purity which is suitable for human consumption. Technical requirements must also be fulfilled (aggression against piping, prevention of sedimentation). Limits which permit water to be released as drinking water are specified by law and oriented to health issues. In Germany, quality of drinking water is regulated by the Drinking Water Act (TrinkwV 2001). The revised version which came into effect on 1. January 2003 includes implementation of the EC Directive ‘on the quality of water for human consumption’ (98/83/EC) into national law. Drinking water must not contain any pathogenic germs. The water must be colourless and odourless, palatable and stimulate to consumption on account of its natural state. The limits for nitrate and nitrite are very low. Contamination as a result of over-fertilization in agricultural areas in recent years has led to problems in many regions in which drinking water supply relies on extraction from ground water. A minimum level of minerals should also be included. The most frequent minerals dissolved by water are calcium and magnesium carbonate as well as sulphates of these metals.

Their concentrations are specified as the hardness (German hardness) of the water. Drinking water should have at least 5° and at least 25 ° German total hardness (dH). The pH value must be between 6.5 and 9.5.

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